不同高度柔性植被对坡面流水动力特性的影响

基于系列坡面流试验,研究了柔性植被的高度(4 cm,8 cm和15 cm)对坡面流水动力特性的影响.研究表明:覆盖率相同时,4 cm植被阻水效果最好,15cm最差,而该差异随着坡度增大而减小.4 cm和8 cm植被覆盖时,水流阻力系数随雷诺数增加先减小后增加,这是由于雷诺数较小时水流阻力主要以床面阻力为主,雷诺增大时主要以植被阻力为主.另外,通过染色剂法测得光滑床面平均流速修正系数为0.2～0.4,有植被覆盖床面为0.4～0.8,且修正系数随平均流速增大而增大.     

Eddy current analogy of torsion problem

In as paper, an eddycurrent analogy and a brief sketch of required equipment are presented. Values oftorsional rigidity and shearing stresses of a prismatic bar under free torsion can be obtained experimentally to a high degree of accuracy in an instant with this equipment whether the cross-section is bounded bv a single boundary or multi-connected boundaries. The error is les than two per cent generally, as shown in Table 3- ’Hits new analogy can be used extensively to solve various physical problems expressed by Poisson’s (or Laplace’s) equation with constant boundary condition.     

城市典型植被的热辐射特性研究

植被在改良土壤、防风固沙、净化环境、调节气候以及人类生存等方面具有不可替代的重要作用,因此植被研究是地球生态环境研究中不可或缺的内容。而日趋成熟的热红外监测技术则为植被研究提供了一种更快捷、更有效的手段。通过对吉林省长春市典型地面植被的亮度温度进行测量,得到了不同类型植被的热辐射特性。研究了不同角度、不同波段、不同时相和不同类型植被的热辐射特性。结果表明,植被类型对植被的亮度温度影响较大,波段对植被的亮度温度影响较小,测量时间对植被的亮度温度影响明显,探测角度对植被的亮度温度影响较大。该实验为植被类型的进一步精确识别和分类提供了重要依据。     

浙江省森林植被的水平分布与垂直分布

本文将浙江省水平分布的现状森林植被分常绿阔叶林(以红楠林;甜槠、木荷林;细柄蕈树、青冈、红楠林为代表),常绿,落叶阔叶林(以青冈,麻栎林;苦槠,枫香林;石栎,化香林为代表)及落叶阔叶林(以化香,黄连木、麻栎林;白栎,短柄枹林,枫杨林为代表)并以西天目山,括苍山及龙泉风阳山的森林植被的垂直分布为例,说明浙江省的森林植被的垂直分布. 最后提出,植被的分布,因受人为及小环境的多种因子的影响,不能机械地以当地的大气候条件,作出绝对的界限划分的见解,以及恢复浙江山地植被的的办法.     

赣江沿岸植被及其生态对策

本文记叙了赣江沿岸的植被,同时提出了赣江存在的主要问题及其相应的生态对策,为赣江的治理提供科学依据。另外,对赣江的划分提出了新的观点。     

监测小麦叶片氮积累量的新高光谱特征波段及比值植被指数

实时、快速、无损监测作物氮素状况对于精确氮肥管理具有重要意义。传统的氮素估测方法在时间或空间上难以满足要求,新兴的高光谱遥感技术为作物氮素监测提供了有效手段和技术途径。本研究的目的是基于三个田间试验的系统观测资料,探索可用于小麦叶片氮素监测的新的高光谱敏感波段及比值指数。利用减量精细采样法,系统构建了350～2 500 nm范围内所有两两波段形成的比值光谱指数RSI(ratio spectral index),综合分析了小麦叶片氮积累量LNA(leaf nitrogen accumulation)(g N·m-2)与RSI的定量关系,发现了监测叶片氮积累量的新高光谱特征波段(990, 720)和光谱指数RSI(990, 720),建立了相应的监测模型y=5.095x-6.040,模型的决定系数(R2)为0.814。利用独立试验资料检验模型,决定系数(R2)为0.847,相对根均方差(RRMSE)为24.70%,表明模型预测值与观察值之间的符合度较高。因此,利用高光谱比值指数RSI(990, 720)来估算小麦叶片氮积累量是精确可行的。该结果为便携式小麦氮素监测仪的研制开发及遥感信息的快速提取提供了适用可行的波段选择与技术依据。     

青海湖地区植物微量元素自然背景值及其特征

分析了以青海湖区各类植被中采集的４６种主要植物样品的８种微量元素,得到了区内植物和各类植被的微量元素自然背景值。为植物微量元素学、青海湖地区生态环境研究所 、草原建设、蓄业发展以及生物地球化学找破等提供了基础资料。     

Leaf overlay effects on the transmittance of thick and thin film microstripline

This paper reports the differences in the transmittance characteristics in the X and Ku band (8–18?GHz) of thick film and thin film microstripline due to leaf overlay. Two types of leaves are studied?—?Tradescantia (Magenta coloured leaf) and Pothas Scandens (Green leaf). The changes in the moisture content in the leaf produces frequency, surface, orientation and type of metallization dependent changes in the characteristics of the microstriplines. Thick film and thin film microstriplines react differently when there is deficiency of chlorophyll in the leaf overlay. An approximate estimate of the effective dielectric constant of the leaf has been made using the overlay technique. It is felt that thick film microstripline with leaf overlay can be used to monitor the moisture status of leafy vegetation in the 8–18?GHz frequency range.     

利用遥感影像软件ENVI提取植被指数

在遥感影像处理中,植被指数已被广泛应用于定性和定量评价植被覆盖及其生长活力．本文主要介绍利用ENVI遥感图像处理软件对遥感影像进行植被指数提取4的方法。对植被指数提取的关键部分进行了分析,并给出了植被指数提取的技术关键．     

Concentration of Bioactive Phenolic Compounds in Olive Mill Wastewater by Direct Contact Membrane Distillation

Olive mill wastewater (OMW), generated as a by-product of olive oil production, is considered one of the most polluting effluents produced by the agro-food industry, due to its high concentration of organic matter and nutrients. However, OMW is rich in several polyphenols, representing compounds with remarkable biological properties. This study aimed to analyze the chemical profile as well as the antioxidant and anti-obesity properties of concentrated fractions obtained from microfiltered OMW treated by direct contact membrane distillation (DCMD). Ultra-high performance liquid chromatography (UHPLC) analyses were applied to quantify some phenols selected as phytochemical markers. Moreover, α-Amylase, α-glucosidase, and lipase inhibitory activity were investigated together with the antioxidant activity by means of assays, namely β-carotene bleaching, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) diammonium salts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and Ferric Reducing Activity Power (FRAP) tests. MD retentate—which has content of about five times greater of hydroxytyrosol and verbascoside and about 7 times greater of oleuropein than the feed—was more active as an antioxidant in all applied assays. Of interest is the result obtained in the DPPH test (an inhibitory concentration 50% (IC₅₀) of 9.8 μg/mL in comparison to the feed (IC₅₀ of 97.2 μg/mL)) and in the ABTS assay (an IC₅₀ of 0.4 μg/mL in comparison to the feed (IC₅₀ of 1.2 μg/mL)).